What is the skill of dividing history into eras based on important features called?

explanation:

i think it is in quadrant 4.

the five year plans were part of a command economy. there was little choice in what would be emphasized for the current 5 year period.

the answer to democracy or totalitarianism is a bit harder. in stalin's time, russia was totalitarian. now that's not entirely true. putin has moved towards at least the boundary.

john maynard keynes developed new economic theories in response to the : b) great depression of the 1930s. his theories are so important that they are known as "keynesianism". in his works he supports the idea of a government with deeper involvement and intervention to end the great depression.

(d). gave voting rights to free african americans and white women.